Small vase on a conical foot and with a pear-shaped body and flaring mouth, called heishi. Heavy, dark brown stoneware, decorated with bands of cobalt blue that oxidized partially into various hues of gray-black, covered by a clear glaze. 

This type of flask is typical for the Okinawa/Ryukyu islands. The decoration, too.

Ryukyu pottery. Okinawa, Japan, early 20^th century, perhaps a little earlier.

H 5.5 x diam at foot 2.25 in.

Underside mouth chipped and partially repaired; minuscule glaze chip at foot.

Similar pieces are in the Saga Kenritsu Kyushu Toki Bunkakan (The Kyushu Ceramic Museum), illustrated in their catalog “Okinawa no yakimono”, items 60 through 65.